ST-7 gravitational reference sensor technology development program

In 2003, Stanford University completed a technology development program of a next generation gravitational reference sensor (GRS) for the New Millennium Program. This program culminated in the validation of GRS technology to technology readiness level 5 with a combination of laboratory experiments, manufacturing demonstrations and simulations. The core of the GRS is a test mass that is free to float inside a housing. When the sensor is flown on the LISA pathfinder spacecraft, the GRS test mass will follow a purely gravitational trajectory to within 3×10^-14 m·s^-2·Hz^-12/ at 1 mHz - a four order of magnitude improvement over current technology. In This work we describe the technology development program, the results of a series of experiments and a simulation of the full system.